A cell-based integrated circuit (IC) is a type of an application specific integrated circuit (ASIC).
That is, the cell-based IC is a semi-custom large-scale integrated circuit (LSI) designed and manufactured by combining various logical cells prepared in advance as a library.
The cell-based IC is, for example, configured as an IC by mixing large-scale circuit blocks (mega cells or macro cells) and basic standard cells (basic circuits).
The cell-based IC realized by the standard cells may include random logics.
Conventionally, a cell-based semi-custom designing method has been widely used in designing an ASIC.
In this designing method, common intellectual properties (IP) registered to a library are combined and an automatic layout wiring tool is used, thus promoting the enhancement of efficiency in IC designing.
As ICs are advancing toward the reduction in size, charges are accumulated in a wiring pattern due to an etching process, or the like of an IC, and the charges flow to a device through a gate electrode to generate a so-called antenna effect of degrading the characteristics of the device.
Various techniques for preventing the antenna effect have been proposed.
In the related art, the solutions to the general antenna effect include restraining a length of a wiring directly connected to a gate electrode to restraining an antenna ratio and increasing an area of an antenna diode to increase a maximum ratio.
Here, the antenna ratio refers to a ratio of an area of a signal wiring (metal wiring) connected to a gate electrode to an area of the gate electrode (a gate area) in a CMOS transistor. Further, the antenna diode is used to release accumulated charges.
However, the countermeasures to restrain the length of a wiring directly connected to the gate electrode in order to restrain the antenna ratio and increase the area of the antenna diode in order to increase the maximum ratio, and the like, in a situation in which a gate area is reduced as ICs are increasingly reduced in size, have problems in that wiring convenience are lowered and usage efficiency of an area is degraded.